Assessing the transport and fate of MTBE amended petroleum hydrocarbons in the UK Chalk aquifer

solinst petroeum fuel formulations downhole geophysical fracture logging verticle hydraulic profiling multilevel sampling verticle solute profiles distribution of contaminants image

G P Wealthall, S F Thornton and D N Lerner
Groundwater Protection and Restoration Group,
University of Sheffield, UK



The ether oxygenates MTBE and TAME have been used in petroleum fuel formulations in the UK since the mid-1980s and have led to contamination of major aquifers, including the Chalk aquifer of southern England. An assessment is made of the controls on the fate of MTBE, TAME and BTEX compounds at a petroleum fuel-contaminated site on the Chalk aquifer, using a novel package of investigation methods. The approach involves initial conceptualisation of the LNAPL source term and dissolved phase plume, with further site characterisation using combined rock core and downhole geophysical fracture logging, vertical hydraulic profiling and multilevel sampling of vertical solute profiles to understand the distribution of contaminants and biodegradation processes in the aquifer.

The current understanding of the transport and fate of MTBE and TAME in groundwater is generally based on laboratory and field studies undertaken in North America. There is very little information on the behaviour of these constituents in UK aquifers. The research described here is the first reported study of the transport and fate of MTBE and TAME in a European dual-porosity aquifer.